Mechanism for converting rotary motion to linear reciprocating motion



April l 1, 950 J. R. HEFLER NEORANISM FOR CONVERTING ROTARY MOTION TO LINEAR REOIPROOATING MOTION 2 Sheets-Sheet l Filed July 4, 1945 INVENTOR J0 /2. /e/Ye Emu/m ATTORN EYS WON .1w O

Wm w April l l, 1950 .1. R. HEFLER NEOHANISM FOR OONVERTINO ROTARY MOTION TO LINEAR REOIPROOATING MOTION 2 Sheets-Sheet 2 Filed July 4, 1945 f .W l 0. N1

wvl-:mon Hex/7er ATTORNEYS 1 lIlIllIl[lll/lilll/lllll/IIIIll/IH Patented Apr. 11, 1950 Stdt? MECHANISM FOR CONVERTING `ROTARY MOTIN TO LINEAR RECIPROCATING MOTION .John R. Hc'er, Providence, R. I.

Application AJuly 4, 1945, .Serial No.v 603,228

(Cl. i4-44) 11 Claims.

vThis invention relates to anadjustable .mechav nism for converting rotary motionto linear reciprocating motion, lparticularly its application to reciprocating plunger or diaphragm pumps of lthe type employed to meter or proportion various` fluids.

It yis desirable to provide in a kmechanism of this character means for changing `the amplitude of movement of the -reciprocated part while in .motion by means of some yelement normally stationary relative to the moving part of the device. vIt is also desirable to control the movement of the reciprocated part so as to accelerate .its rate of travel in one direction and retard its rate of travel in the opposite direction.

An object of .the .invention is the provision of .a mechanism in vwhich the-amplitude of movefment of the reciprocated part maybe controlled vof vtravel of the reciprocated .part will be from a predetermined iixed point at all amplitudes of movement of thereciprocated part.

Another objectro the invention is. the provision for controlling the'rate of movement in either direction of travel of the reciprocated part.

A more speciiicobject-*of the invention is :the 'provision of a crank mechanism for a .pump in which the amplitude of movement of the 'pump plunger may bevaried while in motion.

Another object of the `invention is thegprovivsion of va. crank .mechanismior apumpsin which the amplitude vof motion ofthepmnp-.plunger may be 'varied at l constant clearance of pump plunger.

Another object ofthe invention is .the'provi- 'sion of a crank mechanism Vfor a vpump in which Zthe amplitude of movement of the pump 4plunger may be varied Whilejin 'motion by means of a part 4normally stationary.

Another object of the invention is the provision 'of a crank mechanism for a pump in which ,l lthe. rate of movement of the .pump plunger Ain either direction may be controlled.

vWith these and other objects in view, the .inventionconsists vof .certain .novel .features fofconstruction, .as will be more .fully described andV "2 particularly pointed out `in the `appended claims.

In the accompanying drawings: Fig. -1 is a sectional view of a crank mechanism, .a crosshead Vslideand a pump .combined fembodyingmy invention;

Fig. 2 `is an elevational view partially insection or the crank mechanism .shown in Fig. 1 on anenlarged scale;

Fig. 3 is a sectional view takensubstantiallyon lineB- of Fig..2;

Fig. 4 is .an exploded view .showing elements .formingpart of lthe.crankmechanism;

Fig. 5 is adiagram showinga partial cycle .of motion of the CrankmechaniSm; v

Fig. 6 is a A.plan vewffpartially in section showing the means iur transmitting .motion to the .crank mechanism; and

lFig. '7 is adiagrammatic view of. a modied constructionof a crank mechanism.

VIn general the invention comprises a crank mechanism in which .twocranks are provided and which arehereinafter designated as guide members. These guide members are positioned opposite to each .other `and rotated about axes which extend substantially parallel .to each other and which can vbe spaced in non-coaxial relation to each other. .Each guide member has a linear .guiding .element orelements thereon ,at right .an-

.gles to the axis of rotation. The crank .pin .is .inthe form of a floating 4eccentric located between two guide members having .guide elements on .either side .thereof at an angle with each other, which .slidably engage the two guide members.

The engagement of the crank pin is vsuch as .to transmit positive rotary .motion directly from one guidemember .to the other while maintainving vixed angles between their `guide elements. Rotationof the guide members when they are not coaxial produces .aneccentric motion .of .the crank ivpin since the apexvof the angle .between the guide elements must move in .a circular .path between the .axis-of the Aguide members. This is due .to the fact-.that in a circleallinscribed anglessubtended by the same are are equal and therefore the locus of the apex of a xed angle between two points-will be :the arc of a circle connecting the two points.

The size of the circle will be determined by the axial displacement between the Aguide `memment.

.bers and is zero when the two guide members members so that when the axis of one guide `.melnber is `xed and the other moved the ampli-A tude of throw and the center will be changed. If the guide elements on the crank pin are at right angles on its axis, the crank pin will provide a crank motion in a circle whose diameter is equal to the axial distance between the guide members. In the mechanism means are provided for moving the axes of rotation of the guide members in relation to each other so as to decrease or increase the throw of the crank pin by predetermined amounts. A connecting rod, eccentric strap or other linkage is provided for operatively connecting the crank pin to a member guided for linear reciprocating motion, which may be straight line or curvilinear as desired.

The mechanism may also include a rotary variable speed device which can be made to alternately accelerate and slow down the rotation of the guide members so as to vary the rate of travel of the reciprocating guided member in one direction from that in the other direction.

Referring to the drawing for a more detailed description of the invention in which there is shown in Figs. 1 to 6, one embodiment of the invention, I8 designates generally the crank mechanism. This comprises a crank pin I I which is mounted between oppositely disposed cranks or guiding members l2 and I3.

Each guide member is provided with a guide element I4 therein, which in the present instance is in the form of a groove I5 that extends diametrically across the face thereof, with the groove in one member positioned opposite and at substantially right angles to the groove in the opposite guide member. The crank pin Il has on opposite sides tongues I6 which also extend substantially diametrically across the face thereof, with the tongue on one side positioned at right angles to the tongue on the opposite side. The tongues in cross section conform to the cross section of the grooves and are slidably received therein and maintain the grooves at a xed angle relative to each other. The rotation of one guide member will be transmitted to the other guide member directly through the tongue and groove connections therebetween.

Extending from the guide member I2 there is a shaft I'I which is journaled in a bearing I8 provided in a housing I9 which encloses the crank mechanism. The housing may contain a lubricant in which the parts may rotate. A collar 28 is secured to the shaft and engages against a shoulder 2I surrounding the bearing I8 and prevents lateral movement tending separation of the guide members. The member i3 has a stub shaft 22 extending therefrom and parallel to shaft I'I. This shaft 22 is journaled in a bearing block 23 which is mounted for slidable movement between guide strips 24 and 25 provided on a. side wall 26 of the housing. The bearing block has a threaded opening 21 extending therein and is threadedly engaged by the shank portion of a captive adjusting member 28 which is rotatably mounted on the end wall 30 of the housing. A knob 3l is secured to the member 28 for manually rotating the same. Rotating the member 28 will slidably move the bearing block 23 to increase or decrease the spacing between the axes of the guide members depending upon the direction of rotation of member 28.

In order to predetermine the spacing between the axes of the guide members I2, i3, I provide an indicator 32 which comprises a pin 33 secured to the bearing block 23 to move therewith. The pin extends through a slot 34 in the wall 26 and is provided with a pointer 35 which will move '4 over a scale 38 graduated in appropriate increments so as to indicate the relative spacing between the axes of the guide members I2 and I3.

A pitman or link 31 is provided with a bearing opening 38 in which is journaled the crank pin II. The link 3'I is pivotally secured to a guided member 3S which may be in the form of a cross head guide 40 of a pump mechanism generally indicated 4I and having a usual pump plunger 42 actuating in a cylinder .3 having inlet and outlet ports dit, 45. The cross head may comprise a reciprocal member 40a guided in a cylinder 40h. In order to provide for overloads on the crank mechanism, the member 400. is connected to member 38 by means of a weak link device such as a shear pin 40e.

The operation of the crank mechanism thus far described is as follows; Rotary Imotion is transmitted at equal velocities from guide member l2 to guide member I3, through the tongue and groove connections between the guide members and `crank pin. This in effect provides for the crank pin to be driven or moved equally by each guide member. The angle formed at the center of intersection of the grooves I5 will be a fixed right angle at all positions of rotation. The limit of movement of the crank pin center is conned from the axis of one guide member to the axis of the other guide member. Since the crank pin is free to move relative to each guide member and is equally moved thereby, its center will assume a position at the center of intersection of the grooves I5 in all positions of rotation. Therefore, in accordance with the geometrical fact that an angle inscribed in a semicircle is a right angle, the crank pin center will move in a circular path passing through the axes of the guide members I2, I3. This circular path will be described from a point or axis midway on a straight line passing through the axes of rotation of the guide members. Thus, the spacing of the axes of rotation of the guide members will determine the position of the axis of rotation of the crank pin center.

It will be apparent that the bearing block 23 may be moved to increase or decrease the spacing between the axes of rotation of the guide members so as to change the amplitude of motion of the reciprocated guided member from zero movement to maximum while in motion.

In Fig. 5 the plotting of the crank pin center as it will occur due to various positions of angu larity or rotation of guide members is illustrated.

A, B, C represent the axis vof members I2, I3 and crank pin II respectively, lines a-a, b-b the grooves in members I2, I3 and lines e-c', e-e the tongues in the crank pin. In the assumed position B and Cv will be coaxial to each other. If lines a-a and b-b are advanced to position shown by lines indicated 4E, 69, then lines d-d' and e-e will also be advanced to position 46, 49. The intersection of these lines will be at position which will locate position of C. Thus relocating the position of (Las at 5I, 52, and 53 will describe a circle representingy the path of travel of C intersecting the axes of guide members I2, I3. It will be noted that for each half revolution of the guide members I2, i3 a complete revolution of crank pin center about its axis of revolution will be had. Thus for each rotation of guide members there are two rotations of the crank pin, which provides two complete reciprocations of the guided member 39.

Each of the axes of rotation ofthe guide members I2, I 3 intersect'the'axis of'reciprocation of agico'sioov the guidedmem'ber' 39?- SinceL the-aShat'T His lxedin position-j theechange in direction' ofFtra-vel of Tthe reciprocatedmemberfatA Ione endh offits Apath offtravelfisfat-a fixed'loca-tion. When the crank mechanism;v is` employed" to reciprocate the plunger or diaphragm ora pump andftlief'lzero dis'- placement` of'- the plunger or diaphragnr of the pump-has been1 establislried;`5 then. any change in the; amplitude ofthe-crank movement willbefhat a` constantzero clearance of-pump.l

` Inforderl toprovide for'reciprocatingjthe=guided memberf 39` at a greater` velocity` in'` one/:direction of*t travel' than in the* other; I' provide-a rotary variable speed-'devicei-M; Thedeviceein' the present instanceis in therform of aepluralityfof universal couplings--f55`- and' 56 joined f in series. 'I'he couplingv 55 is-providedwith' a socket-portion 51 which adjustably receivesthe reduced end portion 58'of-'the-shaft-l11and afscrewbolt Sill-adjustably secures 4rthe-portion 51 in 'positionon the shaft.' The coupling-56 also has4v a=socket end portion in'V which"A is received-f the reduced end portion ofv 'ai mainf drive'fshaft' 6i The* opposite endsfoiftheA couplings areftelescopicall'y' and: rotatably connectedifto-each yother-as at a: A screw bolt-'62secures the portion 60'to the shaft; These couplings have the property `of alternately speeding Iup andslowing-'d'own twice in each revolution. The velocity oithespeeding upandslowing down may be varied" by changing the relative angularity between the` coupling. Thisl isV accomplished in the present instance by loosening the bolt 59 andrelativelysliding'thefreduced end portion 58 in or out of the socket portion 51.

The deviceL 54 may be adjusted-to bein timed charge and' a retard movement-on the-r suction stroke.

In Fig. 7 I have shown a modied arrangement of crank mechanism which is shown diagrammatically. The guide members 63, 64 in the present instance each comprises a bar 65 having ears 66 formed at each end. The ears 66 have aligned guide openings 61. The bars extend through the axes of rotation thereof and are positioned to extend at right angles to each other. The member' 63 has a shaft 68 extending therefrom and is it journaled in a xed bearing 69. The member 64 is provided with a stub shaft 10 extending parallel to shaft 68 and is journaled in a slidably mounted bearing block 1I. The block 1! is threadedly engaged by a captive adjusting member 12 provided with an enlarged head portion 13 for manually rotating the same. The shafts may =be relatively moved towards or away from each other by rotating the member 12 in the proper direction. The crank pin 14 is provided with right angularly extending rods 15 which are slidably received in guide openings 61. The link for transmitting reciprocating motion from the crank pin to the member 16 which is rectilinearly guided l in a bearing 18 is in the present instance in the form of a yoke 19. The yoke has an elongated slot 80 through which the crank pin 14 extends and is also provided with oppositely extendingarms 8|, 82. The arm 8| is secured to the mem- 6 ber^16; arm'. 82.? isL alsofrectilinear-ly: guided ir'rbearirig-'83.`

The'operation ofl the' modifiedr crank? mechanis'm' issii'nilarA tirthatV7 shown in* the 'other figures the-V` diawir'ig;y Rotary motion may be'A transmitted tolshaft". 681by'afdevice 5'4'1 inI a manner similar tothatabovef described.v A's the crank pin d'lislmovedf thesamewill' recipro cate the yoke 1`9`-'and"`theguic'leol'`member-- 16'-1 secured' thereto.

The luse: oi'fthe term plunger as hereinl employedI is? intended' tof-include any-1 such' devices whichY are employedffr lchanging the volume: of aV `pump ycylinder' andlwhich are` reciprocat'ed; for examplesuch asa plunger, piston, or diaphragm.

I claim:

l AL mechanism for i convertingv rotary motion toi-linear:reciprocating motiony comprising a link', a guidedl member `attachedI tosaid` link and' reciprocated thereby; means for rotating one-end portion of saidi'link i'n a'circulary path., andi-means includingv anormally stationary member manue ally operableforshifting the axis about which said linkf'end'rotates.'

2. A mechanism forconvertingrotary motion tolinear reciprocatingmotion comprisingv a link, a'A` guidedlmemberfattached'ito said link and reciprocatedi thereby, means yfor'rctating one end portion of saidlink inf* acircular path, and' means including a normal-ly stationary member-movable independently off'the rotationv of 'said link end I'portion' forsh'ifting- 'the axisabout which said linkL endn portion'rotates:

3": A- mechanism orsconvertingrotary motion to vlinear. reciprocatingV motion'comprisingh a" link, a" guided" member attach'edto` said' link' and reciprocatedltherebyJ means forfreciprocating-said link including rotary guide members' operatively connectedto said link, oneiend portionof said link-rotating inI a" path intersecting -the axesof rotationof saidguide members, said guidel members rotating about axes movable relative to each otherrandimeansffor relativelyshifting, the axes about whichsaidiguide members Arotate to change the amplitudeof reciprocation ofsaid link.

4i A' mechanismjfor" converting rotary motion to'linear reciprocating motion comprising a link, a guidedmember attachedto' said link and reciprocated thereby, means for reciprocating said link including rotary guide members operatively connected to said link, one end portion of said link rotating in a path intersecting the axes of rotation of said guide members, a bearing movably mounted and in which one of said guide members is journalled, and means for moving said bearing for varying the axial spacing between said guide members for shifting the location of the axis about which said end portion of the link rotates.

5. A mechanism for converting rotary motion to linear reciprocating motion comprising a link, a guided member attached to said link and reciprocated thereby, means for oscillating said link including oppositely positioned rotary members rotatable about axes spaced from each other and each having a guide thereon extending at substantially right angles to each other, an intermediate member journaled in said link and slidably engaging said guides and movable relative thereto and rotated thereby in a circular path about an axis extending centrally between the axes of said rotary members.

6. A mechanism for converting rotary motion to linear reciprocating motion comprising a link, a guided member attached to said link and reciprocated thereby, means for rotating one end 7 portion of said' link including oppositelyl positioned rotary members rotatable about axes spaced from each other and each having a guide thereon extending at substantially right angles to each other, an intermediate member journaled in said link and slidably engaging said guides and movable relative thereto and rotated thereby in a circular path about a shiftable center extending centrally between the axes of rotation of said rotary members, said intermediate member moving in a path intersecting the axes of rotation of said rotary members, and means for relatively moving .said rotary members to and from each other to shift the axis about which said intermediate member rotates.

'7. A mechanism for converting rotary motion to linear reciprocating motion comprising a crank mechanism, a guided member attached to said crank mechanism and reciprocated thereby, a

constant speed rotary power source, a quick return motion device operatively connected to said power source and crank mechanism for transmitting motion from said power source to said crank mechanism including a pair of shaits extending generally in end-to-end relation and connected to each other by a universal joint, and means for adj-usting said device for controlling the rate of travel of the guided member in one direction relative to the other.

8. In a pump, a plunger, a crank motion for reciprocating said plunger comprising rotary guide members, one of said guide members being rotatable about a xed axis, the other of said guide members being rotatable about an axis movable to and from the said xed axis, a crank pin slidably mounted on said guide members and movable relative thereto and revolved thereby `in a path intersecting the axes of rotation of said Aguide members, a link operatively connected to said plunger and to said crank pin for transmitting motion from said crank pin to said plunger, and means for moving the movable axis to and from said iixed axis for changing the amplitude of movement of said crank pin.

9. In a pump, a plunger, a crank pin having oppositely spaced guides extending at an angle with each other, a pair of rotating guide members engaging said guides, means for spacing the axes of rotation of said guide members, a, link connecting said plunger to said crank pin, a constant speed power source, and a quick return motion device operatively connecting said guide members to said power source.

10. A mechanism for converting rotary motion to linear reciprocating motion comprising a crank mechanism, a guided member attached to said crank mechanism, and reciprocated thereby, a constant speed rotary power source, and a quick return motion device comprising a pair of shafts connected to each other by a universal joint with one of said shafts connected to said power source and the other of said shafts connected to the crank mechanism for transmitting motion from said power source to said crank mechanism.

11. In a pump, a cylinder, a plunger reciprocable in said cylinder, means including a link for reciprocating said plunger in said cylinder, means for rotating one end portion of said link in a circular path, said path passing through a point iixed relative to the end of said cylinder, and means including a normally stationary member manually operable for shifting the axis about which said end rotates whereby the stroke of said plunger is adjusted.

JOHN' R. HEFLER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 305,520 Juengst Sept. 23, 1884 460,642 Kitson Oct. 6, 1891 763,742 Emerson June 28, 1904 995,948 Bracken June 20, 1911 1,052,542 Widmer Feb. 11, 1913 1,907,647 Gruman May 9, 1933 2,398,520 Clements Apr. 16, 1946 FOREIGN PATENTS Number Country Date 451,996 Germany Nov. 4, 1927 

